Rates of diagnosis and death from colorectal cancer appear to be shifting to ever younger patients, a new study finds.
These rates appear to be declining among seniors while rising in the young, according to the report in CA: A Cancer Journal for Clinicians.
The median age at diagnosis dropped from 72 in the late 1980s to 66 in the most recent data from 2015-2016, researchers found.
Colorectal cancer is the third most commonly diagnosed cancer and third leading cause of cancer death in the US.
“The message from this report is that the colorectal cancer patient population is rapidly shifting younger,” said study leader Rebecca Siegel of the American Cancer Society. “And the younger patients are unique, including being more often diagnosed with metastatic disease, typically not being screened and having experienced delays in diagnosis.”
Younger patients also are often less financially able to handle a cancer diagnosis, Siegel said. Moreover, their lifespan is going to be longer and so are more likely to experience late effects of treatments. “Some treatments have heart toxicity and there are also late effects associated with radiation treatment,” Siegel said.
No one knows why more young people are developing colorectal cancer, Siegel said. But there are some known risk factors, such as obesity in adolescence and young adulthood. Researchers are looking into other possible risks, such as antibiotic use, which may have impacted the microbiome, Siegel added. Siegel’s team looked at US data from the 1990s through 2016. They found rapid fall in colorectal cancer incidence in people aged 50 and older during the early 2000s, most likely because of increased screening.
Among those aged 50 to 64, rates were declining at about 2% to 3% per year. But between 2011 and 2016, rates in that age group increased 1% per year, while rates among older people continued to drop.
Rates among those under 50 increased by 2.2% per year between 2011 and 2016.
The rising incidence among people under 65 has been driven mostly by trends in non-Hispanic whites, although rates among American Indians and Alaska Natives have also risen steeply, researchers found.
Death rates among those aged 65 and older have been declining by 3% per year and by 0.6% among those aged 50 to 64, while they have been increasing by 1.3% per year in those younger than 50.
In 2020, the researchers project, approximately 147,950 people in the U.S. will be diagnosed with colorectal cancer and 53,200 will die from it, including 17,930 cases and 3,640 deaths among people younger than 50.
The new study follows several others suggesting rates of colorectal cancer are rising in younger people and dropping in seniors, said Dr. Jordan Karlitz, director of the GI Hereditary Cancer and Genetics Program at the Tulane University School of Medicine in New Orleans.
“Young people need to risk-stratify themselves,” Karlitz said. “First, know your family history because if you are at risk, you could end up developing colorectal cancer before you’re at the age for screening average-risk people.”